They've had zero deaths since February: https://graphics.reuters.com/world-coronavirus-tracker-and-maps/countries-and-territories/gibraltar/
It was a misstatement that was later corrected.
Source: https://twitter.com/Posyfish/status/1419416881774178304?s=20
This article leaves out a crucial excerpt from the piece it is quoting:
"The new data do not mean that the vaccines are ineffective. The vaccines still powerfully prevent severe illness and death, as they were meant to, and people with breakthrough infections very rarely end up in a hospital."